Re:Humans evolved to tolerate smoke poisoning [pdf]
by logfromblammo on Friday February 17, 2017 @04:11PM
(#13671738)
You forgot to include the probability that any given mutation occurs in a cell where such mutation can be observed to produce a beneficial effect.
If one cell in your body mutates such that it might protect your lungs against damage from smoke inhalation, it won't do you any good (nor ill, probably) if that cell is in your toenail matrix.
Nor do all cells in the body divide at a uniform rate.
I would guess that the one type of cell most likely to show an effect from non-germline mutation are the hematopoietic stem cells. They produce all types of blood cell, are self-renewing, and blood cells touch every other part of the body. But they are also only 1/10000th of all myeloid cells. There may be only 10^6 HSCs in one body
Also, 10000 generations of ancestors is not 10^4 fertilized eggs. Most people have two parents. 0 generations of ancestors is 1 fertilized egg. 1 generation is 3. 2 generations is 7. 3 generations is 15. The upper limit on N generations is 2^(N+1)-1 fertilized eggs. For 10000 generations, that is 4e3010 cells. Though the number of individuals in the species eventually limits that number, as multiple inheritance causes some of your ancestors to be counted more than once. The lower limit would be the degenerate case where all 10000 generations were siblings that had at least one son and one daughter, and that is 2e4. So quite a lot of room for variability in there.
If one cell in your body mutates such that it might protect your lungs against damage from smoke inhalation, it won't do you any good (nor ill, probably) if that cell is in your toenail matrix.
Nor do all cells in the body divide at a uniform rate.
I would guess that the one type of cell most likely to show an effect from non-germline mutation are the hematopoietic stem cells. They produce all types of blood cell, are self-renewing, and blood cells touch every other part of the body. But they are also only 1/10000th of all myeloid cells. There may be only 10^6 HSCs in one body
Your reference [1] only included the abstract: https://www.researchgate.net/publication/248399628_An_estima...
Also, 10000 generations of ancestors is not 10^4 fertilized eggs. Most people have two parents. 0 generations of ancestors is 1 fertilized egg. 1 generation is 3. 2 generations is 7. 3 generations is 15. The upper limit on N generations is 2^(N+1)-1 fertilized eggs. For 10000 generations, that is 4e3010 cells. Though the number of individuals in the species eventually limits that number, as multiple inheritance causes some of your ancestors to be counted more than once. The lower limit would be the degenerate case where all 10000 generations were siblings that had at least one son and one daughter, and that is 2e4. So quite a lot of room for variability in there.